Biomedical subjects

W S Kim

Publications and source records attributed to W S Kim.

At least 55 records · Page 3Linked to original sources

PubMed2001

CHOP followed by involved field radiation: is it optimal for localized nasal natural killer/T-cell lymphoma?

The present study aimed to analyse the treatment outcome of four cycles of CHOP (cyclophosphamide-vincristine-doxorubicin-prednisolone) followed by involved field radiation therapy (IF RT) for the treatment of stage I-II nasal natural killer (NK)/T-cell lymphoma. From March 1995 to December 1999, 17 patients (median age 41 years; range 30-66) with localized nasal NK/T-cell lymphoma were enrolled. B symptoms were noted in five patients (31%). Sixteen of seventeen patients (94%) were of low risk when classified according to the International Prognostic Index (IPI). The treatment plan consisted of four cycles of CHOP chemotherapy followed by IF RT of 45 Gy. Two patients received radiation during the first or second cycle of CHOP because of bleeding from the primary tumour site. Both patients achieved complete responses (CRs). In the remaining 15 patients, after 4 cycles of CHOP, 6 CRs and 3 partial responses (PRs) were achieved (53% of response rate). IF RT was given to six patients (four in CR, one in PR and one in PD), and all six patients achieved CR. Overall, CR was achieved in 10 of 17 patients (58%). The planned sequential chemoradiotherapy was completed in only 6 of 17 patients (35%) because of the progression during chemotherapy. None of the patients who achieved CR experienced relapse of lymphoma during follow-up. The estimated overall three-year survival rate was 59%. In univariate analysis, B symptoms and stage were significant prognostic factors for response and overall survival (P < 0.05). The present study suggests that four cycles of CHOP followed by IF RT is not satisfactory for treating patients with localized nasal NK/T-cell lymphoma, and that further exploration for improved therapy is needed.

Adult↗

PubMed2001

Purification and characterization of acharan sulfate lyases, two novel heparinases, from Bacteroides stercoris HJ-15.

Two novel acharan sulfate lyases (ASL1 and ASL2: no EC number) have been purified from Bacteroides stercoris HJ-15 which was isolated from human intestinal bacteria with glycosaminoglycan (GAG) degrading enzymes. These enzymes were purified to apparent homogeneity by a combination of QAE-cellulose, DEAE-cellulose, carboxymethyl-Sephadex C-50, hydroxyapatite and HiTrap SP Sephadex C-25 column chromatography with the final specific activity of 50.5 and 76.7 micromol.min-1.mg-1, respectively. Both acharan sulfate lyases are single subunits of 83 kDa by SDS/PAGE and gel filtration. ASL1 showed optimal activity at pH 7.2 and 45 degrees C. ASL1 activity was inhibited by Cu2+, Ni2+ and Co2+, but ASL2 activity was inhibited by Cu2+, Ni2+and Pb2. Both enzymes were slightly inhibited by some agents that modify histidine and cysteine residues, but activated by reducing agents such as DL-dithiothreitol and 2-mercaptoethanol. Both purified bacteroidal acharan sulfate lyases acted to the greatest extent on acharan sulfate, and to a lesser extents on heparan sulfate and heparin. They did not act on de-O-sulfated acharan sulfate. These findings suggest that the biochemical properties of these purified acharan sulfate lyases are different from those of the previously purified heparin lyases, but these enzymes belong to heparinase II.

Amino Acid Sequence↗

PubMed2001

Partial characterization of polyfermenticin SCD, a newly identified bacteriocin of Bacillus polyfermenticus.

AIMS: To characterize polyfermenticin SCD, a newly identified bacteriocin of Bacillus polyfermenticus SCD. METHODS AND RESULTS: Bacillus polyfermenticus SCD was identified as a bacteriocin producer with a bactericidal activity against Bacillus subtilis IFO 12113. Polyfermenticin SCD, named tentatively as the bacteriocin produced by B. polyfermenticus SCD, showed a narrow spectrum of activity against Gram-positive and Gram-negative bacteria, a yeast and moulds. Production of polyfermenticin SCD in a 5 l jar fermenter followed typical kinetics of primary metabolite synthesis. The antibacterial activity of polyfermenticin SCD on sensitive indicator cells disappeared completely by treatment with proteinase K, which indicates its proteinaceous nature. Polyfermenticin SCD seemed to be very stable throughout the pH range of 2.0 to 9.0, and it was relatively heat labile compared with other bacteriocins. Direct detection of polyfermenticin SCD activity on SDS-PAGE suggested that it had an apparent molecular mass of about 14.3 kDa. CONCLUSIONS: Bacillus polyfermenticus SCD produced relatively heat-labile polyfermenticin SCD with a narrow spectrum of activity. SIGNIFICANCE AND IMPACT OF THE STUDY: Bacillus polyfermenticus SCD is a commercial probiotic which has been used for the treatment of long-term intestinal disorders. New findings on polyfermenticin SCD will be valuable in the evaluation of commercial probiotics. Polyfermenticin SCD can be used to control Bacillus spoilage organisms as a biological control agent.

Bacillus↗

PubMed2001

Studies on the overall oxygen transfer rate and mixing time in pilot-scale surface aeration vessel.

An aerated vessel with Simcar type surface aerator was studied to estimate its significant performance characteristics i.e., oxygen transfer rate, mixing time and power consumption. The oxygen transfer and mixing characteristics were investigated with variations in the operating variables such as rotational speed, diameter, bottom clearance of impeller, liquid height and power consumption in single and dual impeller systems. The bottom clearance of the top impeller was found to affect largely the capacity of the impeller by varying the quantity of liquid loaded to it. It was also ensured that surface aeration caused a slight increase in mixing time compared to it under ungassed conditions. The dual impeller system was employed for the purpose of improving oxygen transfer and mixing at TH < 1 varying the types and the bottom clearance of thelower impeller. However, the oxygen transfer rate was independent of the lower impeller mainly depending on the capacity of the top impeller though mixing time was sharply reduced by the lower impeller. The effect of the bottom clearance of the lower impeller was related to the liquid flow pattern inside the vessel, which was presented by computational fluid dynamics (CFD). The oxygen transfer rate and the mixing time were correlated with power consumption within reliable error range.

Bioreactors↗

PubMed2001

Oxygen transfer characteristics in a pilot scale surface aeration vessel with Simcar aerator.

The volumetric mass transfer coefficient, KLa, was determined by dynamic method in a surface aerated pilot scale squared vessel up to 0.531 m3 equipped with Simcar type impeller. Through surface aeration, the oxygen transfer characteristics were investigated with the variations of operating variables such as stirring speed, impeller diameter, liquid height and power input per liquid volume (P0/V). It was seen from the results of different oxygen concentration absorption that the dynamic method might lead to errors in KLa when air was used for absorption. To provide reliable KLa values measured by dynamic, the KLa data using pure oxygen were used and confirmed with feeding steady-state method (FSM). As expected, KLa depends on P0/V, impeller size and liquid height. However, for Simcar type impeller, the KLa shows linear dependency on P0/V in contrast to majority of correlations reported in the literature which shows KLa variation of (P0/V)0.65 for disk type impeller. Moreover, it was interesting to find that the bubble behaviors inside the vessel computed by computational fluid dynamics (CFD) could explain qualitatively the KLa changes with operating variables. For the purpose of scale-up procedures, the empirical correlations for predicting KLa were developed within +/- 2% accuracy.

Adsorption↗

PubMed2001

Treatment of highly polluted groundwater by novel iron removal process.

The removal of ferrous iron (Fe(II)) in groundwater has been generally achieved by simple aeration, or the addition of an oxidizing agent. Aeration has been shown to be very efficient in insolubilization ferrous iron at a pH level greater than 6.5. In this study, pH was maintained over 6.5 using limestone granules under constant aeration to oxidize ferrous iron in groundwater in a limestone packed column. A sedimentation unit coupled with a membrane filtration was also developed to precipitate and filtrate the oxidized ferric compound simultaneously. Several bench-scale studies, including the effects of the limestone granule sizes, amounts and hydraulic retention time on iron removal in the limestone packed column were investigated. It was found that 550 g/L of the 7-8 mesh size limestone granules, and 20 min of hydraulic retention time in the limestone packed column, were necessary for the sufficient oxidation of 40 mg/L of iron(II) in groundwater. Long-term operation was successfully achieved in contaminated waters by removing the iron deposits on the surface of the limestone granule by continuous aeration from the bottom of the column. Periodic reverse flow helped to remove caking and fouling of membrane surface caused by the continuous filtration. Recycling of the treated water from the membrane right after reverse flow operation made possible an admissible limit of iron concentration of the treated water for drinking. The pilot-scale process was constructed and has been tested in the rural area of Korea.

Calcium Carbonate↗

PubMed2001

Corneal hydration affects ablation during laser in situ keratomileusis surgery.

BACKGROUND: Studies in animal eyes indicate that the level of corneal hydration affects the ablation rate of laser surgery; the greater the hydration is, the less the ablation for a given laser pulse. Our study is an assessment in human eyes comparing the effects on ablation by blotting the corneal stromal surface under a corneal flap created for laser in situ keratomileusis (LASIK) procedures between sets of excimer laser pulses, with ablation depth in eyes not blotted between sets of laser pulses. METHODS: We modified the surgical technique for LASIK procedures to assess the effects of the level of hydration on excimer laser ablation depth per pulse. In group 1, 40 eyes underwent LASIK surgery without any modification. Group 2 was composed of 36 eyes having LASIK procedures, but the corneal surfaces were kept relatively dry by blotting of the stromal surface between sets of laser pulses. RESULTS: Six months after surgery, the mean spherical equivalent refractive change was from -8.38 diopters (D) to -1.44 D in group 1 and from -7.93 D to -0.09 D in group 2. For predictability, the deviation from the target refraction after surgery was assessed. Thirty-three percent (13 of 40) in group 1 and 25% (9 of 36) in group 2 were within +/-0.5 D. Forty-eight percent (19 of 40) in group 1 and 50% (18 of 36) in group 2 were within +/-1 D. Six months after surgery, 80% or more in both groups were within +/-2 D. There was myopic regression in all patients. Three months after surgery, regression averaged -0.71 D in group 1 and -1.15 D in group 2. CONCLUSIONS: Corneal hydration levels affect the efficiency of laser ablation in LASIK procedures. With less hydrated corneas, ablation effects were greater than for corneas not blotted during the procedure, but these patients appear to undergo greater myopic regression.

Adult↗

PubMed2001

Mechanistic scheme and effect of "extended sigh" as a recruitment maneuver in patients with acute respiratory distress syndrome: a preliminary study.

OBJECTIVE: To devise a new form of sigh ("extended sigh") capable of providing a sufficient recruiting pressure x time, and to test it as a recruitment maneuver in patients with acute respiratory distress syndrome. DESIGN: Prospective uncontrolled clinical trial. SETTING: Medical intensive care unit of a university-affiliated hospital. PATIENTS: Twenty consecutive patients diagnosed with acute respiratory distress syndrome (18 men, 2 women, age 59 +/- 10 yrs). INTERVENTIONS: From baseline settings of tidal volume (Vt) 8 mL/kg and positive end-expiratory pressure (PEEP) 10 cm H2O on volume control mode with the high pressure limit at 40 cm H2O, the Vt-PEEP values were changed to 6-15, 4-20, and 2-25, each step being 30 secs (inflation phase). After Vt-PEEP 2-25, the mode was switched to continuous positive airway pressure of 30 cm H2O for a duration of 30 secs (pause), after which the baseline setting was resumed following the reverse sequence of inflation (deflation phase). This extended sigh was performed twice with 1 min of baseline ventilation between. MEASUREMENTS AND RESULTS: Airway pressures and hemodynamic parameters were traced at each step during the extended sigh. Arterial blood gases and physiologic parameters were determined before the extended sigh (pre-extended sigh), at 5 mins after two extended sighs (post-extended sigh), and then every 15 mins for 1 hr. In our average patient, the recruiting pressure x time of the inflation phase was estimated to be 32.8-35.4 cm H2O x 90 secs. Compared with the inflation phase, inspiratory pause pressure of the deflation phase was lower at Vt-PEEP 6-15 (28.9 +/- 2.7 cm H2O vs. 27.3 +/- 2.8 cm H2O) and 4-20 (31.8 +/- 2.9 cm H2O vs. 31.1 +/- 2.9 cm H2O; both p <.05). Compared with pre-extended sigh, Pao2 (81.5 +/- 15.3 mm Hg vs. 104.8 +/- 25.0 mm Hg; p <.001) and static respiratory compliance both increased post-extended sigh (27.9 +/- 7.9 mL/cm H2O vs. 30.2 +/- 9.7 mL/cm H2O; p =.009). Improvement in these parameters was sustained above pre-extended sigh for the duration of the study. Major hemodynamic or respiratory complications were not noted during the study. CONCLUSION: We present a new form of sigh (i.e., extended sigh) capable of achieving an augmented recruiting pressure x time through a prolonged inflation on a gradually increased end-expiratory pressure. In view of the sustained effect and absence of major complications in our patients, extended sigh could be a useful recruitment maneuver in acute respiratory distress syndrome.

Airway Resistance↗

PubMed2001

Molecular comparison of pathogenic bacteria from pear trees in Japan and the fire blight pathogen Erwinia amylovora.

Several strains of the genus Erwinia, which were isolated in Japan from pear trees with necrotic symptoms that resembled fire blight, and tentatively identified as Erwinia amylovora, were reinvestigated for their relationship to the fire blight pathogen. These isolates produced ooze on slices of immature pears and were mucoid on MM2Cu agar plates, but did not synthesize levan and did not give the expected PCR signals with several primer pairs specific for Erwinia amylovora. The isolates tested positive with PCR primers designed to detect the novel pear pathogen Erwinia pyrifoliae, which was isolated from Nashi pear trees in South Korea. The nucleotide sequence analysis of a DNA fragment preceding the gene cluster for exopolysaccharide synthesis revealed a closer relationship to Erwinia pyrifoliae than to Erwinia amylovora. Plasmid profiles, protein patterns and genomic DNA analysed by PFGE after XbaI and SpeI digestion were different than Erwinia amylovora. Experiments with strains of Erwinia amylovora isolated from raspberry (Rubus sp.), Erwinia mallotivora and Enterobacter pyrinus also did not reveal a relationship between these bacteria and the Japanese Erwinia strains. The latter are not identical to Erwinia pyrifoliae, but possess many similar features to this pathogen that causes Asian pear blight. It is concluded that pathogenic bacteria isolated in Japan from pear trees with symptoms resembling fire blight are possibly different from Erwinia amylovora.

DNA Primers↗

PubMed2001

Analysis of particle laden flow and heat transfer in cascade and rocket nozzle.

This paper presents results for the calculation of particle trajectories in a cascade and a rocket nozzle using a Lagrangian method. When the floating particles collide to the components, the component surface is damaged severely. The surface erosion rate is strongly dependent on a particle size, a particle impact angle and a surface material. For a compressor cascade, the particle impact rate increases proportionally with the flow inlet angle and the erosion rate on the pressure side surface of blade are related to the surface or coating materials. For a solid rocket nozzle, the particle free zone in the nozzle divergent section increases quickly with increasing particle size and the maximum heat transfer density occurs at the starting region of nozzle convergent section. The Al2O3 droplet breaks up around the nozzle throat due to the high velocity difference between the droplet and gas stream, resulting in the big change of particle free zone.

Journal Article↗

PubMed2001

Survival response and rearrangement of plasmid DNA of Lactococcus lactis during long-term starvation.

The survival response of Lactococcus lactis during long-term starvation was investigated. The cells were cultured with different levels of glucose (the sole energy source) and either were kept in the resultant spent medium or transferred to fresh medium (without glucose) for up to 2 years. The survival of the cells during starvation was not dependent on the nature of transition phase, as expected, but on the nature of medium in which the cells were kept. The proliferation of cells, despite the apparent lack of glucose, could have been due to some cells being able to utilize the small amounts of peptides still present in the spent medium or to use energy sources provided by the breakup of dead cells. The 1- and 2-year-old cultures contained cells with vastly changed morphotypes. When these isolates were examined, it was revealed that the original plasmids present in the parent were rearranged in a certain way, and an entirely new plasmid was generated. Changes were also evident in the chromosomal DNA and in gene expression. Furthermore, all of the isolates exhibited a growth advantage relative to the parent cells when grown in energy-limiting media. When they were tested against different types of stresses, they exhibited a higher resistance against the bile salt and hydrogen peroxide stresses compared to the parent. Because of the similar changes observed in the 2-year-old isolates, a similar survival strategy may be operational in those cells that survive for that length of time.

Bacterial Proteins↗

PubMed2001

Molecular characterization of a new abortive infection system (AbiU) from Lactococcus lactis LL51-1.

This study reports on the identification and characterization of a novel abortive infection system, AbiU, from Lactococcus lactis. AbiU confers resistance to phages from the three main industrially relevant lactococcal phage species: c2, 936, and P335. The presence of AbiU reduced the efficiency of plaquing against specific phage from each species as follows: 3.7 x 10(-1), 1.0 x 10(-2), and 1.0 x 10(-1), respectively. abiU involves two open reading frames, abiU1 (1,772 bp) and abiU2 (1,019 bp). Evidence indicates that AbiU1 is responsible for phage resistance and that AbiU2 may downregulate phage resistance against 936 and P335 type phages but not c2 type phage. AbiU appeared to delay transcription of both phage 712 and c2, with the effect being more marked on phage c2.

Amino Acid Sequence↗

PubMed2001

Cigarette smoke extract induces endothelin-1 via protein kinase C in pulmonary artery endothelial cells.

We examined the mechanism of endothelin (ET)-1 regulation by cigarette smoke extract (CSE) and the effect of platelets on CSE-induced stimulation of ET-1 gene expression in human and bovine pulmonary artery endothelial cells (PAECs). Our data show that CSE (1%) induces ET-1 gene expression (after 1 h) and ET-1 peptide synthesis (after 4 h) in bovine PAECs. The induction of preproET-1 mRNA level was due to de novo transcription, and new protein synthesis was not required for this induction. The protein kinase C inhibitors staurosporine (10(-8) mol/l) and calphostin C (10(-7) mol/l) abolished the induction of ET-1 gene expression by CSE in bovine and human PAECs. Although a lower concentration of platelets (10(6) cells/ml in bovine PAECs; 10(7) cells/ml in human PAECs) did not significantly alter ET-1 gene expression in PAECs, incubation of platelets with CSE (1%) and PAECs produced a significant increase in preproET-1 mRNA and ET-1 peptide compared with the values in the presence of CSE (1%) alone. CSE (1%) induced platelet aggregation and increased the expression of platelet membrane glycoproteins ex vivo. Thus our data suggest that CSE stimulates ET-1 gene expression via PKC in PAECs. CSE and platelets showed a synergistic effect on ET-1 gene expression, possibly through the activation of platelets by CSE.

Animals↗

PubMed2001

Lung cancer in patients with idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) was reported to be associated with increased risk of lung cancer as a result of the occurrence of atypical or dysplastic epithelial changes in fibrosis which progressed to invasive malignancy. In that situation, the cancer will develop in the area of major fibrosis. To investigate the direct relationship between fibrosis and cancer development, the real concordance rate of the two lesions in the chest computed tomography (CT) was analysed and compared to the histological types of lung cancer. The subjects included 63 patients with combined lung cancer and IPF (IPF-CA), 218 patients with lone IPF, and 2,660 patients with primary lung cancer. All patients were diagnosed at Asan Medical Center during the same period. The age, percentage of smokers, and the male sex were significantly higher in IPF-CA compared with lone IPF. The odds ratio of smoking was 2.71 compared to nonsmoking IPF controls. In IPF-CA, 56% of the cancer was located in the periphery of the lung and 52% in the upper lobe. The majority of the cancers (64%) were found in the nonfibrotic area at chest CT. The most frequent cell type was squamous cell carcinoma (35%), and there was no significant difference in the cancer cell type between IPF-CA and total lung cancer population. These findings suggest that in combined lung cancer and idiopathic pulmonary fibrosis patients, the features of the lung cancer are similar to the total lung cancer population.

Aged↗

PubMed2001

Nitric oxide and molsidomine in the management of pulmonary hypertension in Takayasu's arteritis.

We present three patients with pulmonary hypertension in Takayasu's arteritis who showed long-term favorable response, clinically and hemodynamically, to nitric oxide donor molsidomine. In these patients, nitric oxide inhalation was effective in reducing pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR). Molsidomine (single dose of 4 mg p.o.) was also effective in reducing PAP and PVR, but nifedipine was not. With molsidomine, 4 mg tid, dyspnea, exercise capacity, and hemodynamic parameters were improved. These favorable responses have lasted during the 3-month follow-up period in all patients.

Adult↗

PubMed2001

Inducible nitric oxide synthase (iNOS) immunoreactivity and its relationship to cell proliferation, apoptosis, angiogenesis, clinicopathologic characteristics, and patient survival in pancreatic cancer.

BACKGROUND: The clinicopathological and biological significance of the expression of iNOS in pancreatic cancer remains unclear. The goal of this study was to determine the possible roles and clinical significance of iNOS expression in pancreatic cancer. METHODS: Seventy-two pancreatic adenocarcinoma tissue specimens were obtained by surgical resection. We investigated the immunohistochemical expression of iNOS in 72 patients with pancreatic cancer with respect to variable clinicopathological characteristics, proliferation activity (assessed by Ki-67 expression), apoptosis (assessed by TUNEL stain), and microvessel density (assessed by CD34 expression; angiogenesis). RESULTS: Immunohistochemical investigations demonstrated immunolabeling of tumor cells with anti-iNOS antibody. Positivity for iNOS was observed in 48/72 (66.7%). The expression of iNOS protein did not correlate with age, bilirubin, tumor marker, location, size, AJCC stage, differentiation, distant metastasis, or patient survival. No significant association was found between iNOS expression and proliferation or microvessel density in pancreatic cancer. Apoptotic index (AI) of positive iNOS expressions were significantly higher than negative expression (p < 0.001). CONCLUSION: Inducible nitric oxide synthase (iNOS) is expressed by human pancreatic cancer, and its presence is positively correlated with apoptosis of cancer cells that could provide the basis for the development of therapeutic strategies in human pancreatic cancer.

Adenocarcinoma↗

PubMed2001

Cerebellopontine angle ganglioglioma: MR findings.

We present a case of cerebellopontine (CP) angle ganglioglioma in a young child with developmental delay and no trigeminal nerve symptoms. MR imaging demonstrated a mass of homogeneous low signal intensity in the left CP angle on T1-weighted images with no enhancement with gadolinium, and of relatively homogeneous high signal intensity on T2-weighted images.

Cerebellar Neoplasms↗

PubMed2001

The prognosis of respiratory failure in patients with tuberculous destroyed lung.

SETTING: The medical intensive care unit of a tertiary referral hospital. OBJECTIVE: To determine the prognosis of patients whose lungs are damaged by previous and/or present tuberculosis infection and who have subsequently been presented with acute respiratory failure requiring mechanical ventilation. DESIGN: A consecutive series of 38 patient cases with retrospective data analysis. RESULTS: Pulmonary function test results for tests performed within the previous year were made available in 21 of the 38 cases (55%). These showed a mean (+/- SD) forced vital capacity (FVC) of 1.52 +/- 0.46 L (41.0 +/- 14.5% predicted), a forced expiratory volume/second (FEV1) of 0.77 +/- 0.18 L (29.3 +/- 13.6% predicted), and an FEV1/FVC ratio of 55.1 +/- 16.2%. The acid-fast bacilli (AFB) positive group had a significantly higher mortality and more severe lung destruction when compared with the AFB-negative group. Patients with positive AFB were significantly more hypocapnic than those with negative AFB (6.4 +/- 2.7 vs. 9.3 +/- 3.9 kPa, P = 0.020). In multivariate analysis, the level of PaCO2 on admission was identified as the only significant prognostic index (OR 0.76, 95%CI 0.60-0.96). CONCLUSION: Patients with positive AFB smears or cultures may have higher mortality rates than those with negative AFB in the tuberculosis destroyed lung patients with acute respiratory failure. A higher PaCO2 measurement could indicate a better survival rate in this group of patients.

Adult↗